Autoimmune encephalitis typically presents with symptoms, such as psychosis, memory disturbances, seizures, dysautonomia, movement disorders, along with the discovery of novel symptom-related autoantibodies and its clinical scope has steadily grown. Among them, gradually developing dementia, psychosis or anti-epileptic drug-resistant seizures are sometimes misdiagnosed as neurodegenerative, primary psychiatric disease, or idiopathic epilepsy, respectively, and not recognized as candidates for immune therapy. Particularly, those with anti-LGI1 antibodies, frequently identified in limbic encephalitis, reveal subacute and slowly progressive dementia with epilepsy. Detection of disease-specific autoantibodies is useful for proper diagnosis and not missing immune therapy. However, the number of autoantibodies is increasing, which makes it difficult to use them as a diagnostic tool. Commercially available antibody-testing is limited to several autoantibodies. Others need to be sent to certain research laboratories. Additionally, several papers caution about false positive or false negative results occurring frequently and advise testing using several different detection techniques, such as brain tissue immunohistochemistry and live-cell based assays. It is crucial to think about the diagnosis of the patients very carefully not depending on only the results of the autoantibody-test, but rather observing detailed clinical features for proper treatments.
 Author's abstract